Oxygen Sensor Control Behind Catalytic Converter Checking

Oxygen Sensor Control Behind Catalytic Converter, Checking

- Press -C- button.

When indicated on display


Basic Setting Q
Enter display group number XXX

- Press buttons -0-, -3- and -7- to select "display group number 037" and press -Q- button to confirm input.

When indicated on display


System in basic setting 37 ->
1 2 3 4


- Check oxygen sensor voltage in display field 2.
- Check dwell time of oxygen sensor control before catalytic converter in display field 3 and diagnostic result in display field 4.

Display Group 037:

Evaluation display group 037

Display Field 2:

Continuation
If specified value in display field 3 and 4 is not obtained:
- Road test vehicle in order to free oxygen sensor of possible residue and repeat test.

If specified value in display field 3 and 4 is not obtained, even after road test:
- Replace Heated Oxygen Sensor (HO2S) -G39-.


NOTE: If oxygen sensor voltage is OK and dwell time of oxygen sensor control behind catalytic converter is still above 1200 ms, even after a road test, this suggests aging of the oxygen sensor before catalytic converter.


Checking primary voltage







- Disconnect 4-pin harness connector -1- (brown) to Oxygen Sensor (O2S) behind Three Way Catalytic Converter (TWC) -G130-.


NOTE: Coolant reservoir screws must be removed and coolant reservoir must be placed to side in order to access the harness connector. The coolant hoses can remain connected.







- Connect multimeter between terminal 3 and 4 for voltage measurement.
- Switch ignition on.
- Specification: 0.400 to 0.500 V
- Switch ignition off.

If specified value is not obtained:
- Check oxygen sensor wiring.

If specified value is obtained:
- Replace Oxygen Sensor (O2S) behind Three Way Catalytic Converter (TWC) -G130-.

Checking oxygen sensor wires







- Disconnect 4-pin harness connector -1- (brown) to Oxygen Sensor (O2S) behind Three Way Catalytic Converter (TWC) -G130-.


NOTE: Coolant reservoir screws must be removed and coolant reservoir must be placed to side in order to access the harness connector The coolant hoses can remain connected.


- Connect VAG1598/31 test box at wiring harness to Engine Control Module (ECM), do not connect ECM. Refer to "Scan Tool Testing/Wiring and Component Testing Using VAG1598/31 Test Box", Testing and Inspection







- Check following wire connections for open circuit.

Harness connector VAG1598/31 test box
Terminal Socket
3 68
4 69

- Repair open circuit if necessary.
- Check wires to each other for short circuit.

If wire connection is OK:
- Replace Engine Control Module (ECM).